Crystallization and optical properties of finite sized Db-Ga2O3 in sol-gel derived Ga2O3:SiO2 nanocomposites

Gallium oxide nanoparticles embedded in silica matrix with different molar ratios were synthesized by the sol-gel method. Powdered nanocomposite samples were annealed at 400, 500 and 900 deg C. The gallium oxide nanoparticles (2-5 nm) crystallized in the D*b-phase at a very low temperature (~400 deg C) as against the expected temperature ( > 700 deg C), indicating a depression of crystallization temperature under the present condition. This may be a signature of the behaviour of confined nanosized particles. The indications of only Ga-O bonds and Si-O-Si bonds in FTIR spectra and peaks of gallium, oxygen and silicon in energy dispersive x-ray analysis (EDAX) confirmed the non-existence of any impurity. Room temperature photoluminescence study of the samples shows a strong blue emission at ~460 nm.